{"id":870,"date":"2025-11-22T23:42:51","date_gmt":"2025-11-22T23:42:51","guid":{"rendered":"https:\/\/choudhury.com\/blog\/?p=870"},"modified":"2025-11-22T23:58:33","modified_gmt":"2025-11-22T23:58:33","slug":"experimenting-with-valhalla-early-access-build-26-jep401ea21-1-2025-10-10","status":"publish","type":"post","link":"https:\/\/choudhury.com\/blog\/2025\/11\/22\/experimenting-with-valhalla-early-access-build-26-jep401ea21-1-2025-10-10\/","title":{"rendered":"Experimenting with Valhalla Early Access Build 26-jep401ea2+1-1 (2025\/10\/10)"},"content":{"rendered":"\r\n

 <\/p>\r\n\r\n\r\n\r\n

A new build of Valhalla has been made available on https:\/\/jdk.java.net\/valhalla\/<\/a> this version is built on top Java 26 early build.<\/p>\r\n\r\n\r\n\r\n

It’s been a while since I tried to the previous Valhalla Early access in 2022<\/a><\/p>\r\n\r\n\r\n\r\n

A lot has has changed since then.<\/p>\r\n\r\n\r\n\r\n

In the previous version they had concept of value<\/strong> (without identity) and primitive<\/strong> class (without identity and not nullable)<\/p>\r\n\r\n\r\n\r\n

Now they have simplified to value class (without identity)<\/p>\r\n\r\n\r\n\r\n

Whether a value can be nullable is or not, will be delivered separately by this JEP draft: Null-Restricted Value Class Types (Preview)<\/a><\/p>\r\n\r\n\r\n\r\n

Reference Code – No Value class<\/p>\r\n\r\n\r\n\r\n

\n\n
public<\/span> class<\/span> Main {<\/span>
\n    static<\/span> void<\/span> main(<\/span>)<\/span> {<\/span>
\n        long<\/span> start =<\/span> System<\/span><\/a>.currentTimeMillis<\/span>(<\/span>)<\/span>;<\/span>
\n        int<\/span> length =<\/span> 10<\/span>_000_000;<\/span>
\n        Point3D[<\/span>]<\/span> myArray =<\/span> new<\/span> Point3D[<\/span>length]<\/span>;<\/span>
\n        for<\/span> (<\/span>int<\/span> i =<\/span> 0<\/span>;<\/span> i &<\/span>lt;<\/span> myArray.length<\/span>;<\/span> i++<\/span>)<\/span> {<\/span>
\n            myArray[<\/span>i]<\/span>=<\/span>new<\/span> Point3D(<\/span>0f, 0f, 0f)<\/span>;<\/span>
\n        }<\/span>
\n        System<\/span><\/a>.out<\/span>.println<\/span>(<\/span>"Print last value of array : "<\/span>+<\/span>myArray[<\/span>length-<\/span>1<\/span>]<\/span>)<\/span>;<\/span>
\n        Runtime<\/span><\/a>.getRuntime<\/span>(<\/span>)<\/span>.gc<\/span>(<\/span>)<\/span>;<\/span>
\n        printMemoryUsage(<\/span>)<\/span>;<\/span>
\n        System<\/span><\/a>.out<\/span>.println<\/span>(<\/span>"Array length : "<\/span>+<\/span>myArray.length<\/span>)<\/span>;<\/span>
\n        System<\/span><\/a>.out<\/span>.println<\/span>(<\/span>"Total time "<\/span>+<\/span>(<\/span>System<\/span><\/a>.currentTimeMillis<\/span>(<\/span>)<\/span> -<\/span> start)<\/span>+<\/span> " ms"<\/span>)<\/span>;<\/span>
\n    }<\/span>
\n    private<\/span> static<\/span> void<\/span> printMemoryUsage(<\/span>)<\/span> {<\/span>
\n        System<\/span><\/a>.out<\/span>.println<\/span>(<\/span>"MB: "<\/span> +<\/span> (<\/span>double<\/span>)<\/span> (<\/span>Runtime<\/span><\/a>.getRuntime<\/span>(<\/span>)<\/span>.totalMemory<\/span>(<\/span>)<\/span> -<\/span> Runtime<\/span><\/a>.getRuntime<\/span>(<\/span>)<\/span>.freeMemory<\/span>(<\/span>)<\/span>)<\/span> \/<\/span> (<\/span>1024<\/span>*<\/span>1024<\/span>)<\/span>)<\/span>;<\/span>
\n    }<\/span>
\n    static<\/span> class<\/span> Point3D {<\/span>
\n        private<\/span> float<\/span> x ;<\/span>
\n        private<\/span>  float<\/span> y ;<\/span>
\n        private<\/span>  float<\/span> z ;<\/span>
\n        public<\/span> Point3D(<\/span>float<\/span> x, float<\/span> y, float<\/span> z)<\/span> {<\/span>
\n            this<\/span>.x<\/span> =<\/span> x;<\/span>
\n            this<\/span>.y<\/span> =<\/span> y;<\/span>
\n            this<\/span>.z<\/span> =<\/span> z;<\/span>
\n        }<\/span>
\n        @Override
\n        public<\/span> String<\/span><\/a> toString(<\/span>)<\/span> {<\/span>
\n            return<\/span> "Point3D{"<\/span> +<\/span>
\n                    "x="<\/span> +<\/span> x +<\/span>
\n                    ", y="<\/span> +<\/span> y +<\/span>
\n                    ", z="<\/span> +<\/span> z +<\/span>
\n                    '}'<\/span>;<\/span>
\n        }<\/span>
\n    }<\/span>
\n}<\/span><\/div><\/div>\n\n<\/pre>\r\n\r\n\r\n\r\n
 <\/p>\r\n\r\n\r\n\r\n
If I run this on my machine I get this output<\/p>\r\n\r\n\r\n\r\n
Print last value of array : Point3D{x=0.0, y=0.0, z=0.0}
MB: 269.9514617919922
<\/strong>Array length : 10000000
Total time 182 ms<\/strong><\/p>\r\n\r\n\r\n\r\n
 <\/p>\r\n\r\n\r\n\r\n
Now if I do the same using Value class (make Point3D value class)<\/p>\r\n\r\n\r\n\r\n
 <\/p>\r\n\r\n\r\n\r\n
\n\n
public<\/span> class<\/span> Main {<\/span>
\n    static<\/span> void<\/span> main(<\/span>)<\/span> {<\/span>
\n        long<\/span> start =<\/span> System<\/span><\/a>.currentTimeMillis<\/span>(<\/span>)<\/span>;<\/span>
\n        int<\/span> length =<\/span> 10<\/span>_000_000;<\/span>
\n        Point3D[<\/span>]<\/span> myArray =<\/span> new<\/span> Point3D[<\/span>length]<\/span>;<\/span>
\n        for<\/span> (<\/span>int<\/span> i =<\/span> 0<\/span>;<\/span> i &<\/span>lt;<\/span> myArray.length<\/span>;<\/span> i++<\/span>)<\/span> {<\/span>
\n            myArray[<\/span>i]<\/span>=<\/span>new<\/span> Point3D(<\/span>0f, 0f, 0f)<\/span>;<\/span>
\n        }<\/span>
\n        System<\/span><\/a>.out<\/span>.println<\/span>(<\/span>"Print last value of array : "<\/span>+<\/span>myArray[<\/span>length-<\/span>1<\/span>]<\/span>)<\/span>;<\/span>
\n        Runtime<\/span><\/a>.getRuntime<\/span>(<\/span>)<\/span>.gc<\/span>(<\/span>)<\/span>;<\/span>
\n        printMemoryUsage(<\/span>)<\/span>;<\/span>
\n        System<\/span><\/a>.out<\/span>.println<\/span>(<\/span>"Array length : "<\/span>+<\/span>myArray.length<\/span>)<\/span>;<\/span>
\n        System<\/span><\/a>.out<\/span>.println<\/span>(<\/span>"Total time "<\/span>+<\/span>(<\/span>System<\/span><\/a>.currentTimeMillis<\/span>(<\/span>)<\/span> -<\/span> start)<\/span>+<\/span> " ms"<\/span>)<\/span>;<\/span>
\n    }<\/span>
\n    private<\/span> static<\/span> void<\/span> printMemoryUsage(<\/span>)<\/span> {<\/span>
\n        System<\/span><\/a>.out<\/span>.println<\/span>(<\/span>"MB: "<\/span> +<\/span> (<\/span>double<\/span>)<\/span> (<\/span>Runtime<\/span><\/a>.getRuntime<\/span>(<\/span>)<\/span>.totalMemory<\/span>(<\/span>)<\/span> -<\/span> Runtime<\/span><\/a>.getRuntime<\/span>(<\/span>)<\/span>.freeMemory<\/span>(<\/span>)<\/span>)<\/span> \/<\/span> (<\/span>1024<\/span>*<\/span>1024<\/span>)<\/span>)<\/span>;<\/span>
\n    }<\/span>
\n    static<\/span> value class<\/span> Point3D {<\/span>
\n        private<\/span> float<\/span> x ;<\/span>
\n        private<\/span>  float<\/span> y ;<\/span>
\n        private<\/span>  float<\/span> z ;<\/span>
\n        public<\/span> Point3D(<\/span>float<\/span> x, float<\/span> y, float<\/span> z)<\/span> {<\/span>
\n            this<\/span>.x<\/span> =<\/span> x;<\/span>
\n            this<\/span>.y<\/span> =<\/span> y;<\/span>
\n            this<\/span>.z<\/span> =<\/span> z;<\/span>
\n        }<\/span>
\n        @Override
\n        public<\/span> String<\/span><\/a> toString(<\/span>)<\/span> {<\/span>
\n            return<\/span> "Point3D{"<\/span> +<\/span>
\n                    "x="<\/span> +<\/span> x +<\/span>
\n                    ", y="<\/span> +<\/span> y +<\/span>
\n                    ", z="<\/span> +<\/span> z +<\/span>
\n                    '}'<\/span>;<\/span>
\n        }<\/span>
\n    }<\/span>
\n}<\/span><\/div><\/div>\n\n<\/pre>\r\n\r\n\r\n\r\n
Print last value of array : Point3D{x=0.0, y=0.0, z=0.0}
MB: 269.80834197998047
<\/strong>Array length : 10000000
Total time 224 ms<\/strong><\/p>\r\n\r\n\r\n\r\n
Oh dear \ud83d\ude41 actually ran slower using value class !<\/p>\r\n\r\n\r\n\r\n
 <\/p>\r\n\r\n\r\n\r\n
Currently (in this build for now) value class is restricted to 64bit for flattening.<\/p>\r\n\r\n\r\n\r\n
The point3d class has 3 floats = 32 * 3 = 96 bits<\/p>\r\n\r\n\r\n\r\n
In additional there is also an extra bit also added to keep track of whether the value is null or not.<\/p>\r\n\r\n\r\n\r\n
So it’s actually (32 * 3) +1 = 97 bits<\/p>\r\n\r\n\r\n\r\n
 <\/p>\r\n\r\n\r\n\r\n
Why 64bit restriction for flattening, apparently that is to align with size of registers which are 64 bits, otherwise if you need multiple registers, you are in danger of tearing – where threads might be able to read an inconsistent value.<\/p>\r\n\r\n\r\n\r\n
 <\/p>\r\n\r\n\r\n\r\n
However, in the EA build there is an option to create an array of value classes where you can accept tearning might occur and also specify the values cannot be null<\/p>\r\n\r\n\r\n\r\n
 <\/p>\r\n\r\n\r\n\r\n
Replace these lines<\/p>\r\n\r\n\r\n\r\n
\n\n
for<\/span> (<\/span>int<\/span> i =<\/span> 0<\/span>;<\/span> i &<\/span>lt;<\/span> myArray.length<\/span>;<\/span> i++<\/span>)<\/span> {<\/span>
\n    myArray[<\/span>i]<\/span>=<\/span>new<\/span> Point3D(<\/span>0f, 0f, 0<\/span>)<\/span>;<\/span>
\n}<\/span><\/div><\/div>\n\n<\/pre>\r\n\r\n\r\n\r\n
 <\/p>\r\n\r\n\r\n\r\n
with this instead (but note this using a jdk internal class ) so you will need to use this additional command line flags

–add-exports java.base\/jdk.internal.value=ALL-UNNAMED –enable-preview<\/strong><\/p>\r\n\r\n\r\n\r\n
\n\n
Point3D[<\/span>]<\/span> myArray =<\/span> (<\/span>Point3D[<\/span>]<\/span>)<\/span> ValueClass.newNullRestrictedNonAtomicArray<\/span>(<\/span>Point3D.class<\/span>, 10<\/span>_000_000, new<\/span> Point3D(<\/span>0f, 0f, 0f)<\/span>)<\/span>;<\/span><\/div><\/div>\n\n<\/pre>\r\n\r\n\r\n\r\n
 <\/p>\r\n\r\n\r\n\r\n
Full Code (Enabling Null-Restriction and Non-Atomicity )<\/p>\r\n\r\n\r\n\r\n
\n\n
import<\/span> jdk.internal.value.ValueClass<\/span>;<\/span>
\n
\npublic<\/span> class<\/span> Main {<\/span>
\n    static<\/span> void<\/span> main(<\/span>)<\/span> {<\/span>
\n        long<\/span> start =<\/span> System<\/span><\/a>.currentTimeMillis<\/span>(<\/span>)<\/span>;<\/span>
\n        int<\/span> length =<\/span> 10<\/span>_000_000;<\/span>
\n        Point3D[<\/span>]<\/span> myArray =<\/span> (<\/span>Point3D[<\/span>]<\/span>)<\/span> ValueClass.newNullRestrictedNonAtomicArray<\/span>(<\/span>Point3D.class<\/span>, 10<\/span>_000_000, new<\/span> Point3D(<\/span>0f, 0f, 0f)<\/span>)<\/span>;<\/span>
\n        System<\/span><\/a>.out<\/span>.println<\/span>(<\/span>"Print last value of array : "<\/span>+<\/span>myArray[<\/span>length-<\/span>1<\/span>]<\/span>)<\/span>;<\/span>
\n        Runtime<\/span><\/a>.getRuntime<\/span>(<\/span>)<\/span>.gc<\/span>(<\/span>)<\/span>;<\/span>
\n        printMemoryUsage(<\/span>)<\/span>;<\/span>
\n        System<\/span><\/a>.out<\/span>.println<\/span>(<\/span>"Array length : "<\/span>+<\/span>myArray.length<\/span>)<\/span>;<\/span>
\n        System<\/span><\/a>.out<\/span>.println<\/span>(<\/span>"Total time "<\/span>+<\/span>(<\/span>System<\/span><\/a>.currentTimeMillis<\/span>(<\/span>)<\/span> -<\/span> start)<\/span>+<\/span> " ms"<\/span>)<\/span>;<\/span>
\n    }<\/span>
\n    private<\/span> static<\/span> void<\/span> printMemoryUsage(<\/span>)<\/span> {<\/span>
\n        System<\/span><\/a>.out<\/span>.println<\/span>(<\/span>"MB: "<\/span> +<\/span> (<\/span>double<\/span>)<\/span> (<\/span>Runtime<\/span><\/a>.getRuntime<\/span>(<\/span>)<\/span>.totalMemory<\/span>(<\/span>)<\/span> -<\/span> Runtime<\/span><\/a>.getRuntime<\/span>(<\/span>)<\/span>.freeMemory<\/span>(<\/span>)<\/span>)<\/span> \/<\/span> (<\/span>1024<\/span>*<\/span>1024<\/span>)<\/span>)<\/span>;<\/span>
\n    }<\/span>
\n    static<\/span> value class<\/span> Point3D {<\/span>
\n        private<\/span> float<\/span> x ;<\/span>
\n        private<\/span>  float<\/span> y ;<\/span>
\n        private<\/span>  float<\/span> z ;<\/span>
\n        public<\/span> Point3D(<\/span>float<\/span> x, float<\/span> y, float<\/span> z)<\/span> {<\/span>
\n            this<\/span>.x<\/span> =<\/span> x;<\/span>
\n            this<\/span>.y<\/span> =<\/span> y;<\/span>
\n            this<\/span>.z<\/span> =<\/span> z;<\/span>
\n        }<\/span>
\n        @Override
\n        public<\/span> String<\/span><\/a> toString(<\/span>)<\/span> {<\/span>
\n            return<\/span> "Point3D{"<\/span> +<\/span>
\n                    "x="<\/span> +<\/span> x +<\/span>
\n                    ", y="<\/span> +<\/span> y +<\/span>
\n                    ", z="<\/span> +<\/span> z +<\/span>
\n                    '}'<\/span>;<\/span>
\n        }<\/span>
\n    }<\/span>
\n}<\/span><\/div><\/div>\n\n<\/pre>\r\n\r\n\r\n\r\n
With above the output is now<\/p>\r\n\r\n\r\n\r\n
Print last value of array : Point3D{x=0.0, y=0.0, z=0.0}
MB: 40.89228820800781
<\/strong>Array length : 10000000
Total time 109 ms<\/strong><\/p>\r\n\r\n\r\n\r\n
\ud83d\ude42<\/p>\r\n\r\n\r\n\r\n
Wow!! From 270 mb <\/strong>we went down to 41 mb<\/strong> ! a huge reduction in memory usage!<\/p>\r\n\r\n\r\n\r\n
Also the execution time was reduced from 182ms to 109ms<\/strong><\/p>\r\n\r\n\r\n\r\n
 <\/p>\r\n\r\n\r\n\r\n
Hopefully this will be promoted from preview to something that ships in Java soon. Can’t wait!<\/p>\r\n","protected":false},"excerpt":{"rendered":"
  A new build of Valhalla has been made available on https:\/\/jdk.java.net\/valhalla\/ this version is built on top Java 26 early build. It’s been a while since I tried to the previous Valhalla Early access in 2022 A lot has has changed since then. In the previous version they had concept of value (without identity) … <\/p>\n
Continue reading “Experimenting with Valhalla Early Access Build 26-jep401ea2+1-1 (2025\/10\/10)”<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[3,25],"tags":[20],"class_list":["post-870","post","type-post","status-publish","format-standard","hentry","category-java","category-valhalla","tag-java"],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/choudhury.com\/blog\/wp-json\/wp\/v2\/posts\/870","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/choudhury.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/choudhury.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/choudhury.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/choudhury.com\/blog\/wp-json\/wp\/v2\/comments?post=870"}],"version-history":[{"count":33,"href":"https:\/\/choudhury.com\/blog\/wp-json\/wp\/v2\/posts\/870\/revisions"}],"predecessor-version":[{"id":903,"href":"https:\/\/choudhury.com\/blog\/wp-json\/wp\/v2\/posts\/870\/revisions\/903"}],"wp:attachment":[{"href":"https:\/\/choudhury.com\/blog\/wp-json\/wp\/v2\/media?parent=870"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/choudhury.com\/blog\/wp-json\/wp\/v2\/categories?post=870"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/choudhury.com\/blog\/wp-json\/wp\/v2\/tags?post=870"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}